1. Field of the Invention
The present invention relates to a system and a method for processing an image of an object shot by an infrared camera mounted in a mobile body and displaying image information regarding the object on an image display device mounted in the mobile body, a program for imparting the image information processing function to a computer, and an automobile as the mobile body provided with the system.
2. Related Background Art
Conventionally, there has been suggested a technique for performing image processing such as gray scale or binarization processing of a two-dimensional image of an object shot by an infrared camera and thereby recognizing an image area according to the object before highlighting it on the image display device (for example, refer to Japanese Patent Laid-Open No. 2003-134508). Moreover, there has been suggested a technique for performing image processing using parallax of a three-dimensional image of an object stereographically shot by two infrared cameras and thereby recognizing an image area according to the object before highlighting it on the image display device (for example, refer to Japanese Patent laid-Open No. 2002-298298). If these techniques are employed, for example, for an automobile, it is possible to get a driver of the automobile, which is running on a road at night or in poor visibility, to easily recognize the existence of a pedestrian or the like that cannot be easily distinguished by the naked eye.
According to the two-dimensional image processing, there is a case where a plurality of image areas are recognized according to a single object through binarization processing of a gray scaled image (“a splitting phenomenon” occurs). For example, in the state where a single image area A is highlighted according to a single object O as shown in FIG. 6(a), if the distance between a camera and the object is decreased, a splitting phenomenon may occur to thereby highlight three image areas A on the image display device according to the single object O as shown in FIG. 6(b) in some cases. Such a situation confuses an automobile driver or other person who is viewing the image display device and further may cause him or her to feel insecure about reliability of the image.
Moreover, the three-dimensional image processing is of inferior followability to image fluctuations of the object being shot by the camera. For example, in the state where the image area A according to the object O is recognized as shown in FIG. 7(a), if the camera moves slightly downward and thereby the image of the object O moves slightly upward, the recognized image area A insufficiently follows the image movement of the object O as shown in FIG. 7(b). Particularly when the object is far from the camera, even if slightly the camera moves, the image movement of the object becomes large. Such a situation makes the driver feel a sense of incongruity between the non-followability of the image area to automobile pitching or other movements and the driver's bodily sensation and further may cause him or her to feel insecure about reliability of the image.